SELECT * FROM t_emp;

DELETE FROM t_emp WHERE emp_id >= 8;

SELECT emp_id AS empId, emp_name AS empName, emp_salary AS empSalary, emp_age AS emAge FROM t_emp;

INSERT INTO t_emp(emp_name, emp_salary, emp_age) VALUES();

UPDATE t_emp SET emp_name = ?, emp_salary = ?, emp_age = ? WHERE emp_id = ?;

DELETE FROM t_emp WHERE emp_id = ?

SHOW VARIABLES LIKE 'autocommit';

BEGIN;

INSERT INTO t_emp(emp_name, emp_salary, emp_age) VALUES('张三', 123.45, 34);

COMMIT;

CREATE TABLE t_bank(
   id INT PRIMARY KEY AUTO_INCREMENT COMMENT '账号主键',
   account VARCHAR(20) NOT NULL UNIQUE COMMENT '账号',
   money  INT UNSIGNED COMMENT '金额，不能为负值') ;
   
INSERT INTO t_bank(account,money) VALUES
  ('zhangsan',1000),('lisi',1000);
  
SELECT * FROM t_bank;

UPDATE t_bank SET money = money + ? WHERE id = ?;
UPDATE t_bank SET money = money - ? WHERE id = ?;